SU1114348A3 - Method for consolidating soil - Google Patents

Abstract

A METHOD FOR IMPROVING SOIL STRENGTH, which includes immersion into the ground of an injector, feeding a fluid cement material under pressure through an injector, measuring and recording the pressure of a solution, forming a ground zone and then diving the injector to form adjacent zones of hardened soil, characterized in that soil hardening efficiency, during the immersion of the injector, the strength of the grit is determined and, with a strength less than permissible, a flowable cement mat is supplied The series is based on data exceeding the permissible strength of O) soil.

Description

Phie. 1 The invention relates to the construction of buildings and structures on weak soils, in particular to the strengthening of soils by introducing hardening materials into them. There is a method of increasing the strength of the soil, which includes immersion into the soil of the injector, feeding hardened material into the soil through the injector under a certain pressure, forming a zone of hardened soil and subsequent sinking of the injector with the formation of adjacent columnar hardened zones 1. The closest to the present invention is a method for improving the strength of the soil, which includes immersing the injector in the soil, feeding cement through the injector of a flowing material under pressure, measuring and recording the pressure of the solution, forming reinforced soil zones and subsequent immersing the injector to form adjacent zones of the reinforced soil 12. Disadvantage These methods consist in the fact that they are intended for strengthening of uniform soil depths, therefore for soils having homogeneity of different depth and strength, inhomogeneous hardening takes place, overspending of the hardening material due to its possible release to the surface and unjustified expenditure of energy. All this reduces the effectiveness of known methods. The purpose of the invention is to increase the efficiency of soil consolidation. The goal is achieved by the method of improving the strength of the soil, which includes immersion into the ground of an injector, supplying a fluid cement material under pressure through an injector, measuring and registering the pressure of the solution, forming a zone of hardened soil and subsequent sinking of the hardened soil during immersion of the injector determines k) t the strength of the soil and when the strength is less than permissible, the flowable cement material is supplied under pressure the permissible strength of the soil. FIG. 1 shows the equipment for carrying out the proposed method, a general view; in fig. 2 is a diagram of the distribution of the injected solidified material in the reinforced soil; in fig. 3 - a device for implementing the proposed method with a partial cut; in fig. 4 device version, general view; in fig. 5 shows the node A in FIG. 3; Fig. 6 shows the arrangement of the orifices directed upward at an angle; in fig. 7 shows a variant of the arrangement of the orifices directed at an angle downward; in fig. 8 - a variant of the location of the outlet holes, directed horizontally; in fig. 9 layout of equipment in the implementation of the method. A device for implementing the proposed method includes an injection unit 1, an injection pipe (injector) - 2, an extension element 3, a supply pipe 4, a pressure gauge 5 for measuring the pressure of the material pumped by pump 1 with a drain valve, connected to pipe 4, pump 6 and through sleeve 7 a mixer 8 for preparing a hardening material, for example a flowable cement slurry, and an auxiliary pump 9 for water. The injector 2 in its lower part has a rod 10 with a cone 11 fixed at the lower end with a sharpening angle of 60 °, outlet openings 12 placed on the side surface and a guide sleeve 13. On the rod 10 in the middle and upper parts there are piston broadenings 14 and 15, with the broadening 14 at the extreme upper position of the brush 10 covering the outlet openings 12, which, as shown in FIG. 6-8, can be directed at an angle upwards, at an angle downwards or horizontally. The technology for performing the method with the device described is as follows. Initially, the injector 2 is introduced into the ground to the desired depth, the pump 9 is turned on, and the hose 7 and the pipeline 4 are fed into the injector 2, which affects the piston broadening 15, presses the cone 11 of the stem 10 into the ground, while friction of the stem 10 o the ground is eliminated and the broadening 15 falls below the holes 12, and water flows through them into the surrounding soil. During the outflow of water, there is a sharp drop in its pressure, which is recorded according to the readings of the pressure gauge 5. The average value of the readings of the pressure gauge 5 during the period of pressure buildup is taken-. It is a measure of the strength of the soil. During the period of movement of the cone, it must travel a distance of 10-20 cm. After that, the water is completely removed from the device and a fluid hardening material, such as cement mortar, is pumped through Injector 2 under a pressure exceeding the average value of the soil strength. At this pressure, the broadening 15 of the stem 10, as in the case of water injection, falls below the holes 12, through which the cement mortar enters the ground (Fig. 2). The discharge pressure of the flowing material can also be controlled by the static pressure by changing the height of the discharge pipe (injector) 2 and the extension element 3. The pressure can be adjusted by changing the density of the cement material by varying the ratio between water and cement or by introducing lung cement into the material additives (ash, sawdust). The immersion of the injector 2 can be carried out by giving it a rotation around its axis with the help of the corresponding device 16 (Fig. 4). Example. An injector 2 with a length of 4 m and a cross-sectional area of 10 cm with a cone 11 (point angle 60) was immersed in the ground. Injector 2 was immersed to a depth of 3.1 m. Water 10 was supplied to rod 10, and together with cone 11, it moved 30 cm, after that, broadening 15 moved, but holes 12 and water flowed through them into the ground, while the pressure sharply has fallen. Before the water pressure dropped, the pressure gauge 5 had readings 11 84 1.3 kg / cm or with a cross-sectional area of 156 cm wide, the pressure force was 7.8 kg, and the pressure that held the cone 11 with an area of 10 cm was 78 kg / cm. Based on the known dependencies, the strength of the soil was assumed to be 0.7 kg / cm. In accordance with the accepted value of the strength of the soil, the subsequent cement material was subsequently injected at a pressure exceeding the strength, which was 1.2 kg / cm. Cement material was Portland cement, mixed with water at a ratio of 1: 0.94 by weight, density 1.5 t / m, which corresponded to the density of the hardened soil. After 40 hours, the strength of the soil treated with cement material was in the range of 11.2 kg / cm, while the actual pressure of the material being injected into the soil, taking into account its hydrostatic pressure at the depth of hardening, was 1.4 kg / cm. At each point, the fluid cement material was injected before the pressure of the injection pressure was increased, which indicated that the soil was sufficiently saturated with the material. The distance between the points was taken from the calculation of the contact or even partial overlap of the soil reinforcement zones. The proposed method permits, rat. It is rational to use energy inputs depending on the actual condition of the soil and to carry out directional injection of the hardening material into zones with weaker soil.

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Claims (1)

METHOD FOR IMPROVING SOIL STRENGTH, including immersion of an injector in the soil, injection of fluid cement material through the injector under pressure, measurement and registration of mortar pressure, formation of a zone of hardened soil and subsequent immersion of the injector with the formation of adjacent zones of hardened soil, characterized in that, in order to increase efficiency hardening of the soil, during the immersion of the injector, the strength of the ground is determined; when the strength is less than acceptable, the flowing cement material d pressure exceeding the permissible strength of the soil, 7777777 //, hell? SU MP 1114348 FIG. 1>